Zipper

From Free net encyclopedia

This article is about the fastening device called zipper. For other uses of the word zip, zipper, or the acronym ZIP, see zip (disambiguation).

A zipper (British English: zip fastener or zip) is a device for temporarily joining two edges of fabric together. It is widely used in clothing, luggage and other bags, sporting goods and camping gear (e.g., tents, sleeping bags), and other textiles. Other fasteners used in the same items inclued buckles, buttons, safety pins, laces, snaps (also known as poppers and press studs), and Velcro.

1 Description
2 History
3 Types
4 Bibliography
5 See also
6 External links

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Description

Image:Cerniera lampo chiude.gif The bulk of a zip consists of two strips of fabric tape, each afixed to one of the two pieces to be joined, and each carrying tens or hundreds of specially shaped metal or plastic teeth. Another part, the slider, which is operated by hand, moves along the rows of teeth. Inside the slider is a Y-shaped channel that meshes together, or separates, the opposing rows of teeth, depending on its direction of travel. The friction of the slider against the teeth causes a characteristic buzzing noise, which is probably the origin of the name 'zip'.

Some zips have two slides, allowing variation the opening's size and position. In jackets and similar garments, the opening usually is entirely closed when one slide is at each end; in baggage, the opening usually is entirely closed when the two slides are next to each other, at any position along the zipper.

Zippers have multiple uses:

increasing the size of an opening to allow the passage of larger objects, as in the fly (flies) of trousers or in a pocket
joining and completely separate two ends or sides of a single garment, effectively creating or breaking a circuit, as in the front of a jacket
attaching and completely detaching one separable part of the garment to or from another, as in the conversion between trousers and shorts
decoration

A zip costs a fraction of the total cost of the garment. However, if the zipper fails, the garment may be rendered unusable until the zipper is repaired or replaced.

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History

An early device similar to the zip, "an Automatic, Continuous Clothing Closure", was patented in the United States by Elias Howe in 1851; but it was not of practical use and did not reach the market. Whitcomb L. Judson patented a similar "Clasp Locker", for fastening shoes and boots, in 1891 or 1893, and marketed the invention through his Universal Fastener company. These two designs used hooks and eyes. The true zipper, and the design used today, is based on interlocking teeth. It was invented Gideon Sundback, a Swedish-born immigrant to Canada and an employee of Judson's; he invented the "Hookless fastener" in 1913, and patented it, in 1917, as the "Separable Fastener". The B. F. Goodrich Company coined the name Zipper in 1923, and used the device on tobacco pouches and boots. The zip became popular for children's clothing and men's trousers in the 1920s and 1930s. At this stage, the zip was permanently joined at one end, so could not be used to fasten jackets. Whitcomb died in 1956.

Today, leading global companies such as YKK and Tex Corp make various types of zips including "invisible" zippers, metallic zippers, and plastic zippers.

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Types

Coil zippers form the bulk of the sales of zippers world-wide—the classic zipper. The slider runs on two coils on each side. The "teeth" on this zipper are coils. Two basic types of coils are used. One type uses coils in spiral form, usually with a cord running inside the coils. The other type uses coil in ladder form, also called the Ruhrmann type. This second type is now used only in a few parts of the world, mainly in South Asia.
Invisible zippers' teeth are behind the tape. The tape's color matches the garment's, as does the slider, so that, except the slider, the zipper is "invisible". This kind of a zipper is common in skirts and dresses. Invisible zippers are usually coil zippers.
Metallic zippers are the type found in jeans today. The teeth are not a coil, but are individual pieces of metal moulded into shape and set on the zipper tape at regular intervals.
Plastic-moulded zippers are identical with metallic zippers, except that the teeth are plastic instead of metal. While metal zippers must be painted to match the surrounding fabric, plastic zippers can be made in any color of plastic.
Open-ended zippers use a "box and pin" mechanism to lock the two side of the zipper into place, often in jackets. Open-ended zippers can be of any of the above specified types.
Closed-ended zippers are closed at both ends; they are often used in baggage.

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Bibliography

Henry Petroski: The Evolution of Useful Things (1992); ISBN 0679740392
Robert Friedel: Zipper: An Exploration in Novelty (W. W. Norton and Company: New York, 1996); ISBN 0393313654

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